Alfa 8C Performance Issues: Bad Plugs vs Fuel System Fix

Last month I had similar symptoms with my 2011 Alfa Romeo Giulietta with the 1.4L gasoline engine. The rough idle and jerking during acceleration turned out to be a combination of issues. The main problems found were: Faulty spark plugs causing misfires, Carbon buildup on fuel injectors, Cracked vacuum lines These symptoms match what you describe with your 8C. The uneven running and check engine light are classic signs of ignition system problems. In my case, the spark plugs were completely worn and had incorrect gap spacing. The repair involved: Installing new spark plugs, Cleaning fuel injectors, Pressure testing the fuel system, Replacing vacuum lines After the repair, the engine ran smooth again with no jerking or rough idle. The check engine light stayed off. This was a serious issue that needed immediate attention to prevent damage to the catalytic converter. Would recommend having a complete ignition system diagnosis done first, focusing on spark plugs and coil packs before moving to fuel system components.

Thanks for the detailed feedback on your Giulietta issues. My 8C has been at the shop for 2 days now and they found similar problems with engine misfire caused by worn spark plugs and one failing ignition coil. The air filter was also completely clogged which made the rough idle even worse. Do you remember roughly what you paid for your repair job? Just wondering if the quote I got is reasonable. Also curious if youve had any other issues pop up since getting it fixed?

Great to hear your 8C is being looked after. My final repair bill came to 265 Euro, which covered fixing a leak they found in the exhaust system. The uneven engine running completely disappeared after they replaced the worn spark plugs and faulty ignition coil. Since the repair three months ago, the engine has been running perfectly smooth with no issues. The maintenance really made a difference, no more jerking during acceleration and the idle is now completely stable. The fuel injectors were actually fine in my case, just needed a good cleaning. For your 8C, those symptoms definitely pointed to ignition system problems. With the clogged air filter on top of the spark plug and ignition coil issues, addressing all these together should give you back that signature smooth performance these engines are known for. Most important was catching it early before the crankshaft sensor or other components could be affected by the ongoing misfires. Good timing belt maintenance is also crucial on these engines to prevent future problems.

Finally got my 8C back from the shop today. Total bill came to 890 Euro which seems reasonable given all the work they did. The mechanic showed me the old spark plugs, they were completely shot and had a weird white coating on them. They also found the oxygen sensor was starting to fail which explained some of the error codes. The difference in how it runs now is like night and day. No more rough idle or jerking during acceleration. The engine feels smooth and responsive again, just like when I first got it. The check engine light has stayed off and the power delivery feels much more consistent. Really glad I caught these issues before they caused more damage. The shop did a thorough job explaining everything and even showed me all the old parts they replaced. Much better experience than my last mechanic who just wanted to replace unusual parts without proper diagnosis. Will definitely keep up with regular maintenance from now on to avoid these problems in the future. Thanks again for helping point me in the right direction with the ignition system check.